This is the revision of a competitive renewal for a successful Mental Retardation Research Center (MRRC) in the Civitan International Research Center at the University of Alabama at Birmingham (UAB). The MRRC at DAB builds upon the University's contributions over the past three decades to the field of mental retardation and developmental disabilities. The MRRC's mission is threefold: to increase scientific knowledge about basic developmental neurobiology and factors that affect CNS development;to develop and test preventive interventions for MR/DD;and to advance understanding about effective treatment strategies to ameliorate the personal, familial, and societal consequences of MR/DD. The Center includes 62 participants comprised of 37 investigators who access research core services and another 25 clinicians and scientists who are part of the greater MRRC community but do not access research cores. Investigators from 16 basic science and clinical departments (with 51 funded or pending research projects that will use core supports) will participate. The five major research groups are: (I) Development, function and plasticity of synapses;(II) Molecular biology/genetics of nervous system development and degeneration;(III) CNS infectious diseases and neuroendocrinologic mechanisms;(IV) Diagnosis, interventions and therapies for MR/DD, and (V) Environmental effects on brain development (including behavioral interaction with parent, poverty, peers, and chemicals). An Administration and Biometry Core (Core A) provides scientific leadership, supports population-based studies on mental retardation and neurodevelopmental disabilities, provides database management and biostatistical support, sponsors center-wide scientific seminars and colloquia, encourages innovation and new multidisciplinary collaborations, actively mentors junior MRRC investigators, and oversees administrative functioning. The three research cores are: the Recombinant Technologies Core (Core B), the Developmental Neurobiology Imaging and Tissue Processing Core (Core C), and the Developmental Genomics Core (Core D). Collectively, these cores are designed to promote multidisciplinary collaboration, timely exchange of information and technology advances, attract new investigators to MR/DD research, and promote research activities with other MRRCs, as well as to increase the quality and productivity of funded research projects while demonstrating cost-effectiveness. Of high priority is the inclusion of women and individuals from underrepresented ethnic/racial groups as MRRC scientists, trainees, and participants in research projects.